Re: Black Flies? Do I need to protect the dogs?
I don't know about Black Flies in particular, but back when I had a horse, I used Skin-So-Soft bath oil (the original one) to keep the flies off of him. Back then, they didn't have the one that they have now (I believe it's marketed as a mosquito repellent, maybe). Anyway, I put some in a spray bottle, or on a washcloth, and either sprayed (or wiped) Charlie down with the oil. Works great, and no harsh pesticides in it.
Just remember - it was the original SSS oil (which they still sell). Whatever they have now that's marketed specifically as insect repellent probably has chemicals in it, and I don't know anything about those.